The present invention relates to an evaporator for a refrigerating system which refrigerates an object to be cooled (e.g., water, brine, etc.) by exchanging heat between the object and the refrigerant, and a refrigeration apparatus using the evaporator.
In a structure of large scale, such as a tall building, cool water, which has been chilled by a refrigerating system, is circulated through a pipe arrangement disposed in the structure so that heat is exchanged between the cool water circulating in the pipe arrangement and air present in the spaces of the structure to decrease the temperature of the spaces.
FIG. 8 is a diagram showing an example of a conventional evaporator which may be provided with a refrigerator. In this evaporator, a plurality of bundles of heat exchanger tubes 2 through which water passes is disposed in a staggered form in a cylindrical container 1 into which a refrigerant is introduced.
The plurality of heat exchanger tubes 2 may be divided into two groups, namely, a group of entering tubes which communicate with a water entrance 3 and a group of exiting tubes which communicate with a water exit 4. Water enters from the water entrance 3, passes through heat exchanger tubes 2 of the entering tube group in the container 1 to reach a water chamber (not shown in the figure), and then passes through the heat exchanger tubes 2 of the exiting tube group to exit from the water exit 4. During this process, water is cooled down by heat exchange with the refrigerant introduced into the container 1, and the refrigerant which received heat from the water, in turn, boils and vaporizes.
The vaporized refrigerant is then compressed in a compressor, which is not shown in the figure, and transferred to a condenser.
In the above-mentioned type of evaporator, however, when the refrigerant is boiled around the heat exchanger tubes 2 and vapor is generated, droplets of the refrigerant are often blown upwards by the force of the refrigerant vapor. Then, some of these droplets of refrigerant are sometimes drawn into the above-mentioned compressor and cause problems, such as a decrease in the performance of the compressor or damage to an impeller.
Although attempts have been made to create open passages (i.e., spaces among heat exchanger tubes) along the bundle of the heat exchanger tubes in an up-and-down direction as pathways for bubbles generated when the refrigerant boils, the force of the refrigerant vapor blown upwards from the opening of the passages is increased in this case.
Accordingly, one of the objects of the present invention is to provide an evaporator for a refrigerating system, which is capable of preventing blown upwards of droplets of the refrigerant, and a refrigeration apparatus using the evaporator.
The present invention provides an evaporator for a refrigerating system including a container into which a refrigerant is introduced, and heat exchanger tubes disposed in the container through which an object to be cooled down flows, comprising: a prevention plate disposed above the heat exchanger tubes so that droplets of the refrigerant, which are blown upwards due to boiling of the refrigerant, hit the prevention plate and are prevented from proceeding beyond the prevention plate.
In accordance with another aspect of the invention, the heat exchanger tubes are divided into a plurality of vertically spaced groups so that a space is formed between the groups of the heat exchanger tubes in vertical direction; and the prevention plate is disposed above the space.
In yet another aspect of the invention, the distance between the prevention plate and the heat exchanger tubes at an uppermost level is about 0.5 to 2 times the diameter of a heat exchanger tube which is located at the uppermost level.
In yet another aspect of the invention, the prevention plate has a cross section shaped like an inverted letter xe2x80x9cVxe2x80x9d, xe2x80x9cUxe2x80x9d, xe2x80x9cWxe2x80x9d, etc., and the angle of the prevention plate is designed to be between about 60xc2x0 and 120xc2x0.
In yet another aspect of the invention, an end portion of the prevention plate covers at least a part, preferably, half or all, of a heat exchanger tube which is located at the uppermost level of the heat exchanger tubes and is adjacent to the prevention plate.
In yet another aspect of the invention, a group of the heat exchanger tubes facing an inner surface of the container is disposed so that a space is formed between the group of the heat exchanger tubes and the container along the inner surface of the container; and a prevention plate is disposed above the space.
The present invention also provides a refrigeration apparatus, comprising: a compressor for compressing a refrigerant; a condenser for condensing and liquefying the refrigerant which is compressed in the compressor; a throttling mechanism for reducing the pressure of the liquefied refrigerant; and an evaporator for cooling down an object to be cooled by exchanging heat between the object to be cooled and a resultant condensed and pressure-reduced liquefied refrigerant, and evaporating and vaporizing the liquefied refrigerant, wherein the evaporator is one of the above-mentioned evaporators.